Stadium seating is usually based about beams or the like which are connected either directly or indirectly to a floor or vertical riser in the stadium, individual seats are then connected to the beam by way of a clamp or the like which clamp has one component on the seat and one component which can be placed thereover on the other side of the beam and the two can be interconnected. Generally this means that the system is designed for a particular seating arrangement and although individual seats can be removed and replaced, the actual arrangement of seats is basically fixed.
In an alternative arrangement the beam has been provided with plates or the like which are welded or otherwise permanently attached thereto to which individual seats are connected.
In a still further arrangement, individual seats can be connected to the floor or riser.
These arrangements are very inflexible and are usually designed for the particular stadium in a particular configuration and can not be varied from this.